Fully biodegradable bioplastic made of barley

Researchers at the University of Copenhagen in Denmark developed a biobased plastic material, made from barely starch, which is 100 per cent biodegradable.

Plastic waste is a mounting problem. Islands of it float in the oceans, microplastics are found everywhere from the deepest underwater trenches to our own bloodstream. Only a fraction is property recycled.

To counter this problem, the researchers developed a fully biodegradable material, made of barley starch and sugar beet fibres. The resulting material is strong, yet decomposes in nature within two months.

While there are many bioplastics available, which means they are derived from biobased sources, this does not automatically mean they are also biodegradable, or if they are, this is often a specific scenario, like in industrial composting plants.

The new material is a composite. Its main ingredients, amylose and cellulose, are common across the plant kingdom. Amylose is extracted from many crops including corn, potatoes, wheat and barley, while cellulose is present in all plant matter. Both materials decompose naturally.

Together with researchers from Aarhus University, the research team founded a spinoff company in which they developed a barley variety that produces pure amylose in its kernels. This new variety is important because pure amylose is far less likely to turn into a paste when it interacts with water compared to regular starch.

Amylose and cellulose form long, strong molecular chains. Combining them has allowed to create a durable, flexible material that has the potential to be used for shopping bags and the packaging of goods that we now wrap in plastic. The researchers are already working with two Danish packaging companies to develop prototypes for food packaging, amongst other things.

Photo: Catherine Sheila